BACKGROUND: Recently, with the increasing popularity of dental implant and orthognathic surgery, more and more people pay attention to the structure of mandibular canal and adjacent tissues. However, there are few reports addressing specimen measurements at home and abroad. OBJECTIVE: To measure the anatomical data of mandibular canal and adjacent tissue of mandible specimen to provide reliable reference data and anatomical evidence for alveolus surgery, tooth implantation, and orthognathic surgery. DESIGN, TIME AND SETTING: A controlled observation was performed at the Laboratory of Anatomy, Jilin Medical College between March 2007 and September 2007. MATERIALS: Twenty complete mandible specimens. METHODS: Sixteen adult, ex vivo mandibles with complete dentition and 4 edentulous mandibles were measured in every dental position of sagittal profile and posterior mental foramen in terms of molar, alveolar crest, and mandibular canal. Data were statistically analyzed. MAIN OUTCOME MEASURES: Mental foramen location, horizontal distance from anterior border of mental foramen to anterior border of mental canal, mandibular foramen location, distances from mandibular canal to molar root tip, lingual bone plate of mandible, inferior border of mandible, mandibular buccal bone plate, and alveolar ridge crest. RESULTS: Mandibular canal, located in the inferior region of the mandible body, ran towards the lingual side and was close to the inferior border of mandible and most close to the mandibular molar root tip. It turned towards posterolateral and buccal side in front of mental foramen and then passed through mental foramen. The distance of mandibular canal between edentulous mandible and alveolar ridge crest was obviously shortened. CONCLUSION: Multi-section observation and measurement of ex vivo mandible specimens provide precise, reliable evidence for preoperative design of orthognathic surgery, facilitate surgeons to better formulate surgical proposals, and prevent some complications, including intraoperative massive hemorrhage, interior alveolar nerve injury, mandibular angle fracture, and mental bone lateral wall perforation.